Flushable moisture-retaining sanitary pad

ABSTRACT

A disposable sanitary pad or napkin having a flush-disposable absorbent pad on the upper side and a flush-disposable backing of paper or similar material, with a thin flexible layer of liquidretarding material (such as a greasy or waxlike material) between the two, so that liquid from the pad cannot reach the backing to dissolve it, but liquid reaching the backing from its exposed side will disintegrate it so that it can be disposed of by flushing in a toilet, the thin layer being unable to remain as a film without the support of the backing material, so that it also disintegrates when the backing material disintegrates.

United States Patent I [72] Inventor Phyllis M. Larson 3,171,773 3/1965Estes et al (128/287) 1412 Julie Ave.. McLean, Va. 2210] 3,407,81410/1968 George et al. 128/290 PP ,769 FOREIGN PATENTS 2g 1m d FDe c504,466 7 1954 Canada 128/287 1 562,312 8/1958 Canada 128/296 PrimaryExaminer-Anton O. Oechsle [S4] FLUSHABLE MOISTURE-RETAINING SANITARYAssistant E i A ld W, Kramer PAD Attorney-Max L. Libman 3 Claims, 10Drawing Figs.

[52] US. Cl 128/290 [51] Int. Cl A6lf 13/16 T C A disposable Sanitarypad or napkin having a Fleld of Search flush disposable absorbent pad onthe upper ide and a flush. 296-287Jmqu1red) disposable backing of paperor similar material, with a thin flexible layer of liquid-retardingmaterial (such as a greasy or [56] References cued waxlike material)between the two, so that liquid from the pad UNITED STATES PATENTScannot reach the backing to dissolve it, but liquid reaching the3,444,859 5/ 1969 Kalwaites l28/29OX backing from its exposed side willdisintegrate it so that it can 3,489,148 l/ 1970 Duncan et al 128/284 bedisposed of by flushing in a toilet, the thin layer being una- Re24,38510/1957 Flanders 128/290 ble to remain as a film without the support ofthe backing 2,973,760 3/1961 Dudley 128/290X material, so that it alsodisintegrates when the backing materi- 3,005,456 10/ l 961 Graham128/290X a1 disintegrates.

QATERPROOF LAYER 2 msmsnm 2m 3.5591650 QQ QQQQ- :1 7 cost: 2 F 2 vQATERPROOF LAYER FIG. 6.

b INVENTOR Fl 7 3G MATERIAL 2b funwnfl 2b Phyllis M. Larson GREASE-LIKEATTORNEY FLUSI-IABLE MOISTURE-RETAINING SANITARY PAD The problem ofproviding a sanitary napkin, incontinency pad, disposable baby diaper.geriatric pad. etc.. which can disposed of by flushing it away in atoilet has been a difficult one because the requirement that the entirepad be thus disposable means that it must be made of materials whichwill disintegrate in water, yet, in the case of sanitary napkins formenstrual use, for example. the menstrual fluids will also tend todisintegrate any material which can be disintegrated by flushing. Thisproblem is solved, according to the present invention, by providing apad having a backing covered with a thin film of waterproof materialwhich has no mechanical strength except that provided by the backing onwhich it is spread, so that moisture coming from the pad side of thebacking cannot penetrate to reach the backing, but moisture reaching thebacking from the other side, as occurs when it is flushed in a toilet,will disintegrate the backing, and thereby cause the thin waterprooflayer to be broken up so that it also will be flushed away. As a furtherrefinement, the upper side of the absorbent pad may be provided withdepressed. groovedlike portions which tend to diffuse the flow ofmenstrual fluid and to direct it toward the thicker portions of theabsorbent pad where it can be more readily absorbed.

Sanitary pads made according to the invention are suitable for use withthe menstrual panty" described in US. Pat. application Ser. No. 65 l,760,filed July 7, l967by Phyllis M. Larson, but can be used also withany suitable sanitary napkin belt or girdle, or any situation whereconventional sanitary pads are used.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment, as shown in the accompanying drawings, in which:

FIG. I is a top view of a sanitary napkin according to the invention;

FIG. 2 is a view taken on line 2-2 of FIG. 1;

FIG. 3 is a side view of the napkin shown in FIG. 1;

FIG. 4 is a sectional view taken on line 4-4 of FIG. 1;

FIG. 5 is a view showing a modified form of the invention;

FIG. 6 is a view of another modification assembled but not folded;

FIG, 7 is a sectional view taken on line 7-7 of FIG. 6;

FIG. 8 is a sectional view similar to FIG. 6, but in the final foldedcondition;

FIG. 9 is a sectional view of a different modification; and

FIG. 10 is a final-folded view similar to FIG. 9.

According to the FIGS. in which the invention is exemplified by asanitary napkin, the napkin consists of a backing sheet 2, made of paperor any similar flush-disposable material which will disintegrate uponcontact with swirling water, and an upper absorbent pad 3, also made offlush-disposable material, which may be nonwoven rayon or cotton fibers,crepe paper, wood pulp, or similar material, very lightly compressed toform a self-coherent pad capable of absorbing and retaining a maximumamount of fluid, the individual fibers of the pad being howeversufficiently compressed to somewhat retard absorbency, so that the fluidmaterial does not flow too freely through it. Between the pad 3 and thebacking sheet 2 there is a thin film 4 of greasy or waxy materialforming a waterproof barrier between the pad 3 and the backing 2. Thisfilm may be a silicon ointment, Diaparene Perianal cream (Sterling),cold cream, Plastibase (Squibb), etc., which also serves as a bondingagent between the pad 3 and the backing 2, and to some extent serves tohold the two together. To further hold the two elements together, aheavy crimping track is formed as shown at 6 and 7, which may beaccomplished by crimping rollers, as is well known, in the assembly lineformation of the napkins. This crimping track operation, together withthe cutting operation which cuts the pads to the proper size andtherefore tends to somewhat compress the edge portions 8 and 9 so thatthey are much thinner than the body of pad 3, provides edge regions onthe pad, which not only tend to hold the pad 3 and backing 2 together(in addition to the waterproof film), but also serve to retard the flowof fluid outwardly away from the central longitudinal axis of the pad.and to retain such fluid in the bulky portion of the pad. The upper andlower edges of the pad are similarly compressed, and this compressed rimaround the entire perimeter of the pad tends to not only bind the unittogether. but also tends to retain moisture in the central absorbentportion, to prevent it from seeping out along the edges.

The top surface of the absorbent pad 3 is preferably provided over itsmajor area with closely-spaced dents or depressions 10, which tend todiffuse the flow of fluid reaching the top surface of the pad and tospread it over a larger area of the pad, and also to permit such fluidto more readily enter into the main body portion of the pad, while atthe same time the depressions are so oriented, as will be apparent fromthe FIGS., that they tend to direct the flow of such fluids from the.

area where it first reaches the pad in a longitudinal directiongenerally toward the bulky absorbent portion of the pad. For thisreason, several rows of such depressions are provided as shown at 11 atthe lower end of the pad oriented oppositely from the depressions 9, soas to direct the flow of fluid toward the central portion of the pad.

The backing sheet 2 may be made of any suitable material such as paper,polyvinyl alcohol film, etc., which has a reasonable wet strength, butis not indissoluble in plain water, water with detergent solution, orany chemical composition usually present in septic tanks or seweragesystem. The bonding and waterproof layer 4 may be applied either with ablade or a spray nozzle. or in any known fashion, but must form acomplete film over the surface which it covers, to prevent the entranceof water from the pad to the backing strip. The material employed shouldremain nonhardening for the useful life of the product. and must, ofcourse, be nontoxic to the skin.

The depressions 9 and 1 1 may be omitted in the case where the pad isformed of a relatively coarse-grained material having a somewhat roughor corrugated upper surface, which would tend to produce the samegeneral effect. In this case, of course, the general grain of thematerial should run in a longitudinal direction so as to increase theamount of fluid which is carried by the pad, mainly by working it awayfrom the place of greatest flow, in the center of the pad. The dents ordepressions can readily be formed at the same time that the pad isassembled, by passing the pad under or through rollers which areproperly embossed to form the desired configuration, However, the amountof pressure should be greater on the edges, so as to compact the edgeportions more firmly than the center portion, for the reasons notedabove.

The pad shown in FIG. 1 is suited to be carried in the pocket of amenstrual panty such as shown in the above-referred to patentapplication, or in any similar garment, a tab space 12 being left at thefront of the pad for daintiness in handling a used pad. This can beaccomplished by leaving the backing sheet 2 exposed at the tab portion,the absorbent pad 3 being cut away for this purpose.

FIG. 5 shows a slight modification in which two tabs 13 and 14 areprovided at the ends of the sanitary napkin for attachment to a carriersuch as a belt or any similar device, in lieu of the menstrual panty. Ifthe tab material used is such that crimping alone will not providesufficient bonding between the pad 3 and the backing strip 2, then spotgluing or other means of attachment may be used, but only to an extentsufficient to prevent slippage of the top pad from the lower base, tokeep them together during use and during removal, but to allow each topart from the other when flush ed.

Instead of the backing sheet 2 being made of'paper or other relativelynonabsorbent sheet material, it may he a sheet of absorbent pad materialsimilar to the top sheet 3, but preferably thinner, there being howeverthe same waterproof film 4 between the upper and lower portions toprevent moisture from striking through the lower backing pad; however,if a small amount of moisture does strike through, the second pad wouldtend to absorb this.

FIGS. 6-8 show another way of making a pad according to the invention.In this case. the backing sheet 2 of HO. 1 is extended as shown at 20and then folded over the top of-thc pad. to provide a firmer topsurface. which is yet sufiiciently porous to readily absorb and spreadmoisture. and which may also be suitably crimpcd or indented if desired.

FlGS. 9 and 10 show another fonn similar to FIG. 8. but with thewaterproof layer on the folded side. Instead of being made from a singlesheet as shown in FIGS. 6-10. the top and bottom layers could also bemade from two separate sheets similar to the backing sheet material.

The backing sheet 2. 2a or 2b should be uniformly saturable, ie. a dropof moisture at any point will spread until it is uniformly absorbed.Crepe paper with considerable wet strength is preferred. the wetstrength being only barely sufficient for removal by careful handlingwhen wet by normal use. It should be noted that the greasy layer helpsin this respect, as it tends somewhat to keep the fibers together whenthe backing sheet is damp. although not in swirling water.

It will be apparent that the embodiments shown are only exemplary andthat various modifications can be made in construction and arrangementwithin the scope of the invention as defined in the appended claims.

lclaim:

l. A flush-disposable sanitary pad composed entirely offlush-disintegrating material comprising: a. an upper layer comprising aflush-disposable mass of highly absorbent material, b. a lower backingsheet of flush-disintegrable material secured to the lower side of saidmass. c. a thin. flexible continuously impervious layer offluid-blocking material, incapable of holding itself together in theswirling water of a flush toilet. secured and supported between saidupper layer and said lower backing sheet. said impervious layerextending substantially coextensjvely with the effective area of saidpad to block the passage of fluid from said upper layer to said lowersheet.

2. The invention according to claim 1, said impervious layer being alayer of greaselike material supported by said backing sheet. a

3. The invention according to claim 1, said pad being in the form of anelongated strip. the side and end edges of the strip being compressed tobe thinner than the center portion so as to retard liquid flow from thecenter toward the edges and thus tend to retain moisture in the centerportion of the pad.

2. The invention according to claim 1, said impervious layer being alayer of greaselike material supported by said backing sheet.
 3. Theinvention according to claim 1, said pad being in the form of anelongated strip, the side and end edges oF the strip being compressed tobe thinner than the center portion so as to retard liquid flow from thecenter toward the edges and thus tend to retain moisture in the centerportion of the pad.